Fairchild has strengthened its position in military aviation with its role as the prime contractor for the Air Force's A10 close air support aircraft. Production of the aircraft reached a peak in 1979 and indications are that the Defense Department will buy at least 825 A10s instead of the 733 originally planned. In addition to subcontract work on the Boeing 747, Fairchild recently obtained subcontract awards on the new 757 aircraft for the 1980s and 1990s. In February the company signed a $100 million contract with Saab-Scania of Sweden to produce a series of 30-seat commercial planes for the growing commuter air market. At the end of the year backlog in both government and commercial orders was $1.125 billion, compared with a $1 billion backlog at the end of 1978. During the year, Fairchild was rebuffed in an attempt to add to its 20 percent interest in the Bunker Ramo Corp., a manufacturer of electric connectors and electronic components. The company has also expanded its involvement in the satellite communications field through its American Satellite subsidiary. Continental Telephone Corp. agreed to acquire a 50 percent ownership interest in American Satellite and will work jointly with Fairchild to manage the company's future growth.The two compa nies then entered into two arrangements with Western Union Corp. for a substantial ownership interest in communications satellites.